Waste heat boiler



M. H. KUHNER WASTE HEAT BOILER Filed Dec. 15, 1938 2 Sheets-Sheet 1 April 29, 1941.

M. H. KUHNER WASTE HEAT BOILER Filed Dec. 15, 1938 2 Sheets-Sheet 2 Av OOOOOOOOOOOOOO Aoo ooooooooooo OOOOOOOOO R w m H M M operate Patented Apr. 29, 1941 WASTE HEAT BOILER,

Max B. Kuhner, Worcester, Mass., assignor to Riley Stoker Corporation, corporation of Massachuset gorcester, Mass., at

Application December 15, 1938, Serial No. 245,938

4 Claims.

This invention relates to waste heat boilers, and more particularly to the construction and arrangement of a boiler adapted to generate steam by the heat of waste gases which are delivered to the boiler at comparatively high pressures.

The invention has practical applications in various industries, but is especially useful in connection with the polymerization process for recovering gasoline. In. the performance of this industrial process there is need for a steam boiler which is capable of recovering heat from gases at pressures as high as 50 pounds per square inch. preferably with accurate control of the temperature of the gases leaving the boiler, and it is accordingly the main object of the present invention to provide a waste heat boiler which will efllciently under these conditions throughout a long life of useful service.

It is a further object of the invention to provide a comparatively inexpensive waste heat boiler of the water tube type which will be of simple and compact construction and adapted for use with hot gases supplied at pressures substantialy above atmospheric. 7

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. l is a vertical section through a boiler, the section being taken on the line |-l of Fig. 2;

Fig. 2 is an elevation taken in the direction of the arrow 2 in Fig. l, certain parts being broken away for clearness of illustration;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a section on the line 4-4 of Fig. 1;

Fig. 5 is a section on the line 5-5 of Fig. 4; and

Fig. 6 is an enlarged section on the line 6-6 of Fig. 2.

The embodiment illustrated comprises a horizontal cylindrical steam-and-water drum l0 and a horizontal cylindrical water drum H located beneath the drum l0 and parallel thereto. These drums are connected by a bank of upright water tubes l2 and a second bank of upright water tubes II, the end portions of the tubes being bent to enter the drums radially. The tube banks l2 and I4 are located on opposite sides of the vertical plane which passes through the axes of the drums.

Beneath the lower drum there is provided an upwardly concave head or cap l5, circular in plan and approximately semi-elliptical in vertical section, this member being supported on a suitable ramework i6 therebeneath. The head it is provided with an inlet passage I! which slopes upwardly and inwardly beneath the tube bank I! and an outlet passage l8 which slopes downwardly and outwardly beneath the tube bank l4. On the upper margin of the head ii there is mounted a horizontal circular ring 20 channel-shaped in cross-section, with the flanges of the channel extending outwardly. Two parallel upright plates 2| are welded or otherwise secured to the ring 20 and extend across the ring in a direction at right angles with the drum i I the upper edges of these plates being recessed to receive this drum and support the same. Beneath the drum ll there is provided an upright partition 22 which extends longitudinally of the drum. This partition is formed with an opening 23 therethrough which may be controlled by a damper 24 having an operating shaft 25.

The ring 20 serves to support an upright cylindrical metal casing 21 which surrounds the two banks of watertubes and extends slightly above the upper drum In. This casing is provided with circular recesses or openings 28 into which the ends of the drums l0 and i i extend, with ample clearance between these parts. are formed by short hollow cylinders 29 projecting horizontally from the casing and welded or otherwise secured thereto, the outer ends of the cylinders being closed by outwardly convex caps 30. The caps 30 at one side of the boiler are formed with openings 3| normally closed by cover plates 32,'so that access may be had to the clamps 33 of the manhole covers at the adjacent ends of the drums. The casing 21 is closed at the top by an upwardly convex head or cap 35 circular in plan and approximately semi-elliptical in vertical section. As shown particularly in Figs. 2 and 3, the casing is formed of two sections which are separable along a vertical plane extending at right angles to the drums. The joint between the sections is of flanged and bolted construction, and similar joints are provided between the easing 21 and the upper cap 35 and between the casing and the ring 20 therebeneath.

In order to prevent excessive loss of heat by radiation and to protect the metal parts from the hot gases, 9. lining 3] of suitable refractory, insulating material is applied to the inside of the casing 21 and of the heads l5 and 35. This lin ing may be of monolithic construction, but I prefer to utilize separable blocks, particularly for the portion within the cylindrical casing 21. As shown in Figs. 4 and 5, the blocks may be held in place by vertical metal rods 39 which pass through aligned openings in the blocks, the rods being supported by hooks 40 welded or otherwise secured to the inside of the casing.

Suitable means is provided to direct the hot gases into contact with the water tubes. For this purpose an upright baflie a2 is mounted between the tube banks l 2 and it, this battle extending up- These recesses 28 wardly from the lower drum II and terminating somewhat below the upper drum l0. Baffles M are provided between the tube bank [2 and the adjacent refractory lining 31, and similar baflles 45 are provided between the tube bank l4 and the refractory lining. These bafiles may be secured to the water tubes. It will be noted from Fig. 3 that the baiiles 44 and 45 are shaped as circular segments in plan. It will also be noted from this same figure that the rows of'water tubes increase ln width progressively as they approach the central baflle 42, to conform approximately with the circular shape of the casing 21. Openings 46 (Fig. 1) are provided in the casing 2! to allow access into the space beneath the water tubes, and as shown in Figs. 2 and 3 these openings are normally closed by removable plates 47.

Pipe connections 49-extend upwardly from the upper drumii) to safety valves 50, and a pipe connection 5| extends upwardly from the drum H] to form the main steam outlet of the boiler. At the end of the upper drum l opposite the manhole there is provided a gauge glass 53 to indicate the water level in the boiler. end of the lower drum H opposite the manhole there is provided a feed inlet connection 54 and a blowdown connection 55. These various connections to the drums extend through the adjacent portions of the boiler casing, and a sealed joint is provided between these parts to prevent leakage of hot gases while permitting relative movement of the parts by reason of unequal expansion. For this purpose I utilize the construction shown in detail in Fig. 6, which illustrates the sealing means as applied to the feed connection 54, it being understood that a similar construction is employed ,for the other connections. As shown in Fig. 6 a pipe or nozzle 51 leads outwardly from the drum ll through an opening 58 in-the casing cap 30, this opening being formed by a nozzle 59 having a, flange 60 at its outer end. The feed inlet connection 54 is provided at its inner end with a wide flange Bl which is fastened to the outer end of the pipe 51 by means of screws 62. A corrugated sleeve 64 of comparatively thin flexible metal surrounds the pipe between the flanges 60 and BI, the end portions of the sleeve being fastened to these flanges by suitable bolts 65.

The operation of the invention will now be apparent from the above disclosure. Hot waste gases are delivered to the inlet'll and fiow upwardly in contact with the water tubes l2, over the top of the baffle 42 and thence downwardly in contact'with the water tubes I4 to the outlet l8. A portion of the gases may flow through the by-pass opening 23 past the damper 24, which can be adjusted to control the temperature of the gases leaving the boiler. The cylindrical casing 21 is well adapted to withstand high gas pressures, while at the same time confining the gas flow in the manner required for efiicient transfer of heat to the tubes. Relative movements of the boiler and casing, caused by unequal expansion or otherwise, will be permitted by the flexible sleeves 64 without application of undue stresses to the boiler connections. The

boiler is readily accessible for inspection or repair, it is comparatively simple and inexpensive, and occupies relatively little floor space.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A waste heat boiler comprising an upper At the horizontal cylindrical steam-and-water drum, a lower cylindrical water drum beneath the upper drum and parallel thereto, a ballle extending upwardly from the lower drum, two banks of upright water tubes connecting the drums and located on opposite sides of the baffle, an upright metal casing enclosing the drums and water tubes, means providing a gas inlet passage ad jacent thelower end of one tube bank, means providing a gas outlet passage adjacent the lower end of the other tube bank, a partition beneath the lower drum to separate the inlet passage from the outlet passage, the partition having an opening therein, and a damper to control the opening in the partition.

2. A waste heat boiler comprising an upper horizontal cylindrical steam-and-water drum, a lower cylindrical water drum beneath the upper drum and parallel thereto, a bafile extending upwardly from the lower drum, two banks of upright water tubes connecting the drums and located on opposite sides of the baflle, an upright cylindrical metal casing surrounding the water tubes and constructed to withstand high internal pressures without leakage, the casing being" formed with openings into which the end portions of the drums extend, metal caps closing said openings, a metal cap closing the upper end of the casing, a metal cap closing the lower end of the casing and formed with a gas inlet beneath one bank of tubes and a gas outlet beneath the other bank of tubes, a partition beneath the lower drum to separate the inlet from the outlet, the partition having an opening therein, and a damper to control the opening in the partition.

3. A waste heat boiler comprising an upper horizontal cylindrical steam-and-watcr drum, a lower cylindrical water drum beneath the upper drum and parallel thereto, a baffle extending upwardly from the lower drum, two banks of upright water tubes connecting the drums and located on opposite sides of the baflle, an upright metal enclosure entirely surrounding the drums and water tubes and constructed to withstand high internal pressures without leakage, the enclosure including a metal cap located above the upper drum and a metal cap located beneath the lower drum, means providing a gas inlet passage adjacent the lower end of one tube bank, means providing a gas outlet passage adjacent the lower end of the other tube bank, and a partition beneath the lower drum to separate the inlet passage from, the outlet passage.

4. A waste heat boiler comprising an upper horizontal cylindrical steam-and-water drum, a lower cylindrical water drum beneath the upper drum and parallel thereto. a baffle extending upwardly from the lower drum, two banks of upright water tubes connecting the drums and located on opposite sides of the baiile, an upright cylindrical metal casing surrounding the water tubes and constructed to withstand high internal pressures without leakage, the casing being formed with openings into which the end portions of the drums extend, metal caps closing said openings, 21 metal cap closing the upper end of the casing, a metal cap closing the lower end of the casing and formedwith a gas inlet beneath one bank of tubes and a gas outlet beneath the other bank of tubes, and a partition beneath the lower drum to separate the inlet from the outlet.

MAX H. KUHNER 

